Fault-indicating means for signal systems



Allg- 22, 1939- J. H. wHr-:ELocK FAULT-INDICATING MEANS FOR SIGNAL SYSTEMS original Filed June 4, 1954 Patented Aug. 22, 1939 UNITED STATES PATENT OFFICE FAULT-INDICATING MEANS FOR SIGNAL SYSTEMS chusetts Original application June 4, 1934, Serial No.

Divided and this` application April 15, 1936, Serial No. 74,567

8 Claims.

The present application is a division of my original application, Serial No. 728,812, iiled jointly with Frank Scherma, June 4, 1934, for an Alarm signal system, since issued as Patent No. 2,149,200, on February 28, 1939, and relates particularly toimproved means for indicating the occurrence of a fault, power failure or any abnormal circuit condition which might occur in a system of the character contemplated by the aforesaid original application, or in any other supervised electrical system.

According to the invention of the present application, there is provided an arrangement, whereby the means for indicating troublev in a supervised electrical system is also supervised, with provision being made for additional supervision of the auxiliary trouble indicating means. As a result, any fault in either the supervised system or in the doubly supervised trouble indicating means, is immediately called to attention. The above and other advantageous features of the invention will hereinafter more fully appear from the following description with reference to the accompanying drawing, in which:

Fig. 1 is a schematic view illustrating a signal system, to which there has been applied double or cross supervision of the trouble-indicating means.

Fig. 2 is a fragmentary view illustrating functioning of the trouble-indicating means.

Fig. 3 is a fragmentary view illustrating a modification in the manner of obtaining double supervision.

Fig. 4 is a view of side elevation of a master controller for the system.

Like reference characters refer to like parts in the :dilferent figures.

The invention is shown in Fig. l, for purposes of illustration, as being embodied in an alarm signal system in which signals I, indicated as being of the single-stroke solenoid and plunger type, are shown as each providing an operating winding 2. The windings 2 of the signals I are adapted to 'be connected in sections across the supply mains 3 and 4, with balancing resistors 5 therebetween, by means of a number of pairs of relatively movable contacts 6 and 6a., 'I and la, with such contacts Yforming part of a master controller generally indicated by the reference character A.

Referring vto Fig. 4, the master controller A :comprises a U-shaped magnetic core 8, one leg of which is surrounded by an energizing winding 9, while the lower end of the other core leg sup- '.portsa'main armature I0 andan auxiliary armature i i movabie independently of the main armature. The main. armature l carries a bar I2 on which are mounted, in pairs, a number of contacts 6 and I corresponding to the movable contacts of the several sets of contacts shown in Fig. i for controlling energization of the signal windings 2. These contact arms 6 and 'I are insulated from the bar I 2 at IZal and cooperate with stationary contacts 6a and la mounted on an insulating base I3 carrying the master controller A. Therefore, closure of the main armature I0, in` response to energization of the winding 9, is adapted to simultaneously energize the signal windings 2 in sections according to the connection of the several stationary contacts 6a to the signal windings 2 and the connection of the other contacts la to the supply mainsw3 and 4.

Referring again to Fig. 1, the winding 9 of the master controller A is shown as having one terminal permanently connected to the supply main 3 through an ammeter I4, while the other terminal thereof is connected in series with a number of alarm sending stations I5, I disposed at various` locations throughout the system from where yit is desired to send an alarm. The stations I5 are also in` circuit with the several signal windings 2, with a condenser I6 interposed between the stations I5 and thewindng 9 when the supply mains 3 and 4 are energized from an alternating current source. Each sending station I5 provides a pair of relatively movable contacts Iig and I'Ib, normally closed, so long as the station is in a non-operating condition and, for

purposes of illustration, each station I5 is shown as comprising a contact-actuating member I8 in the Vform of a cam wheel, normally stationary. The function of the cam wheel I8, when rotated, is to open vand close ,the contacts Ilaand I'lb to successively interrupt and r-e-establish the circuit through the stations I5.

Since many .different types of sending stations are employed in re alarm systems, it is unnecessary to further describe the structural details of each station I 5, other than to say that, normally, the position of the cam wheel I8 is such as to maintain, the station contacts ila and lll) closed while the station is in its non-operating condidition. Then, upon actuation of the station. for the purpose of sending an alarm, rotation of the cam wheel I8 momentarily separates the contacts IIa and I'Ib, whereupon engagement of the contacts is re-established, in accordance with the arrangement of the cam projections on the wheel I8. In other words, operation of a sending station I5 results in alternately breaking and re-making the circuit through the station contacts Ila and I'Ib, and obviously the cam wheel I3 can be driven through suitable operating mechanism, not shown, so as to send a number of signal impulses through the system for operating the signal windings 2 in accordance with a code, all as fully described in my aforesaid original application, Serial No. 728,812, now issued as Patent No. 2,149,200

With the parts of the system in the condition shown in Fig. 1, that is, the normal condition in which the system is prepared to send signals, a continuous circuit is maintained from the lower terminal of the winding 9 through the closed contacts Ila and Ilb of the several stations I in series, and from thence to the other supply main l through the windings 2 of the signals l, also in series. Beyond the windings 2, the circuit to the supply main A also includes a resistor I9, and the normally closed contacts 29 and 2i of a time delay cut-out device comprising an operating winding 22 in circuit with one of the contacts 29. In passing to the winding 22 the current also traverses the thermal element 23 of an automatic interruptor.

The circuit interruptor of which the thermal element 23 forms a part, comprises a pair of normally closed contacts Zlia and 24D, which are connected in circuit with a resistor 25 between the main 3 and the lower terminal of winding 9, so as to constitute a shunt around the controller winding of less resistance than the winding 9. The existence of this shunt circuit permits the flow oi only a small supervisory current through the winding 9 of the master controller A, as indicated by the small arrows in Fig. 1, which current also traverses the stations l5, the signal windings 2, thermal element 23 and cut-out winding 22. As a result, the winding 9 of the master controller is not energized suiciently to pull up the main armature I9, so that the several pairs of contacts S and 6a and l, la. which control the energization of the signal windings 2 remain in an open condition.

The strength of' the supervisory current flowing through the winding 9 of the master controller A is suflicient, however, to hold up the auxiliary armature H, as shown in Fig. 4. The free end of the auxiliary armature Il carries a rod 2E extending upwardly in front of the winding 9, and with the armature held up by the supervisory current, an insulating plate 23al at the upper end of the rod is held just clear of Va resilient contact 21 that is normally spaced from a second stationary contact 28. The contact 2l is connected to the supply main 3, while the other contact 28 leads to one terminal of the winding 29 of a trouble signal 30.

The trouble signal 39 is illustrated as being of the solenoid belltype, wherein the winding 29 surrounds a magne-tic plunger 3l. One terminal of the winding 29 is connected to the supply main la, while the other terminal thereof is connected in parallel, through interruptor contacts` 32, to the contact 28 and one terminal of a resistor 33. The other terminal of resistor 33 is connected to main 3 and the resistor 33 serves to reduce current passing through the winding 29 to a very low value, as indicated by the small arrows. With the small supervisory current flowing through the winding 29, the plunger 3l is maintained in a position in which its upper end is partly within the winding 29, and this is the position which the plunger normally occupies in the supervised condition of the circuit.

The contacts 21 and 28 under the control of the auxiliary armature ll are connected across the terminals of the resistor 33, and as long as these contacts are held separated by the raised armature Il, only the supervisory current flows through the trouble signal winding 29. However, upon dropping of the armature Il, as upon the occurrence of an open circuit or ground in the signal system, closure of the contacts 2l and 28 will establish a direct connection of one terminal oi winding 29 to the main 3, with consequent full energization of this winding. This results in the plunger 3l being drawn upwardly into the winding 29, as indicated in dotted lines, to strike the resonant member of the signal a single blow. As the plunger moves to its extreme striking position, it operates one movable interruptor contact member 32 to momentarily break the ow of current through winding 29, whereupon the plunger 3| drops back part way and is immediately drawn upwardly to give another stroke due to reenergiZa-tion of the winding circuit upon reclosure of the contacts 32. In other words, so long as the contacts 21 and 28 remain closed, the trouble signal 39 will sound intermittently to give indication of the existence of some abnormal condition in the signal system.

Upon any interruption of the power supply to the mains 3 and da, or upon the occurrence of any break in the circuit of winding 29, the ow of supervisory current through the winding stops, thereby completely deenergizing the winding and permitting the plunger 3l to drop back to the position shown in Fig. 2, in which only a very small portion. of the upper end of the plunger is disposed within the winding 29. With the plunger 3l in this position, its lower end presses together a pair of contacts 35i which are normally separated when the plunger 3| is partly raised, due to the flow of supervisory current. tacts 34 are connected across the terminals of a resistor 33 that is in circuit with the winding 29 of an auxiliary trouble signal 3B that is adapted -to be energized from an auxiliary source of power, such as a battery B. With the resistance 33" in circuit with the winding 29', the flow of current therethrough is reduced to such a value that a plunger 3l witrn'n the winding 29 is held in a slightly raised position, just out of engagement with normally open contacts 34 connected across the terminals of resistor 33.

Upon closure of the contacts 34, due to the dropping of the plunger 3l to its lowest position, as shown in Fig. 2, the resistor 33 is shunted out and sufficient current then passes through the winding 29 to cause the plunger 3l to strike the resonant member of the signal 30rr a single blow. An interruptor including contacts 32' is also in the circuit of the winding 29", so that the plunger 3l is adapted to give recurrent strokes as long as the winding 29 is energized with full current. Therefore, the aindliary signal 30' is adapted to be operated upon any interruption of the power source supplying the mains 3 and 4a,

or upon any break in the circuit of winding 29.

The resonant members of the signals 30 and 3U', respectively, can have different tones, or different rates of striking, so that the person responsible for the maintenance of the alarm system will know the general nature of the trouble which is indicated by operation or either signal.

Upon failure of the auxiliary power source B, or occurrence of a break in thecircuit of winding 29', the supervisory current through winding 29 will be interrupted and the plunger 3| will drop The con- ,i

to its lo-wermost position to close contacts 34 and shunt out resistor 33. This will cause operation of the trouble signal 30 to indicate failure of the auxiliary power source B, or a fault in the signal 30', and since the signals are preferably mounted adjacent to each other, the condition of the contacts 34 and 34' can be readily ascertained to localize the particular source of trouble.

Referring now to Fig. 3, there is shown a modication in the manner of providing double or cross supervision of both trouble signals and the auxiliary source of supply. In this modified arrangement, one trouble signal is indicated at 35, with its winding 36 having one terminal thereof connected to the supply main 4a in series with the winding 31 of a relay. The other terminal of the winding 36 is connected to the supply main 3 through a resistor 38 which reduces the current passing through the windings 36 and 31 to a very low value, which while not suflcient to operate the signal 35, is suiiicient to cause the winding 31 to hold a bridging member 39 out of engagement with a pair of spaced contacts 40.

The contacts 21 and 28 under the control of the auxiliary armature Il are connected across the terminals of the resistor 38, and as long as these contacts are held separated by the raised armature II, only the supervisory current flows through the trouble signal winding 36 in series with the relay winding 31. However, upon dropping of the armature Il, as upon the occurrence of an open circuit or ground in the signal system, closure of the contacts 21 and 28 will establish a direct connection of one terminal of winding 36 to the main 3, with consequent full energization of the winding 36 to operate the trouble signal 35 and give indication of the existence of some abnormal condition in the signal system.

Upon interruption of the power supply to ther mains 3 and 4a, or the occurrence of a break in the circuit of winding 36, the flow of supervisory current through the windings 36 and 31 is interrupted, thereby completely de-energizing the winding 31 and permitting its bridging member 39 to drop and establish a circuit between the contacts 40. The contacts 40 are connected across the terminals of a resistor 38 that is in circuit with the winding 36 of an auxiliary trouble signal 35', adapted to be energized from an -auxiliary source of power B. The winding 36 is in series with the winding 31 of a relay and with the resistor 38 in the circuit, the ilow of supervisory current is just enough to hold a bridging member 39 under the control of winding 31 out of engagement with a pair of spaced contacts 40. Upon bridging of contacts 40, it is evident that the resistor 38' will be shunted out, whereupon suilicient current passes through the auxiliary trouble signal winding 36 to energize the same. Therefore, the auxiliary signal 35 is adapted to be operated upon any interruption of the power source supplying the mains 3 and 4a, or upon a break in the circuit of winding 36.

Upon any interruption of supervisory current v. in the windings 36' and 31', the bridging member 39 will fall and engage the contacts 40. Since these contacts 40 are connected in parallel with the then open contacts 21 and 28, their closure Will also have the effect of shunting out the resistor 38 to cause full energization of the trouble sign-al winding 36. Therefore, any failure of the auxiliary power source B', or any break in the circuit of Winding 36', will be immediately indicated by operation of the trouble signal 35. Thus, the arrangement of Fig. 3 provides double or system, means for maintaining the flow of a small 1':

supervisory current through said signal insufflcient to cause operation thereof, a second signal for indicating any interruption in the flow of supervisory current through the first signal,

means for maintaining the flow of a small superi' visory current through the second signal, and means for causing the rst signal to operate upon any interruption in the supervisory current through the second signal.

2. In combination with a `normally closed electrical system, a fault-indicating signal for said system providing an energizing winding, means for maintaining the iloW of a small supervisory current through said winding insuiicient to cause operation of said signal, a second signal for indicating any interruption in the ilow of supervisory current through the winding of the rst signal, means for maintaining the ilow of supervisory current through said second signal, and means for increasing the flow of current through the winding of the rst signal to cause its operation upon the occurrence of a fault in, the system, or upon an interruption of the flow of supervisory current through said second signal.

3. In combination with a normally closed electrical system, a fault-indicating signal for said system providing a solenoid and a magnetic striker, means for maintaining the flow of a small supervisory current through said solenoid just suilicient to hold said striker in a slightly raised position without operating the signal, a second fault-indicating signal, and means for causing operation of said second signal upon dropping of the striker of the rst signal, upon any interruption of the supervisory current flowing in said solenoid.

4. In combination with a normally closed electrical system, a fault-indicating signal for' said system providing a solenoid and a magnetic striker, means for maintaining the ilow of a small supervisory current through said solenoid just suicient to hold said striker in a slightly raised position without operating the signal, a second fault-indicating signal providing a solenoid and striker similar to the rst signal, means for maintaining a flow of supervisory current through the solenoid of the second signal, and means for increasing the iow of current through one solenoid to cause its striker to operate in response to dropping of the striker of the other signal upon interruption in the flow of supervisory current through its solenoid.

5. In combination, an electrical circuit, independent normally closed electrical circuits each including fault-indicating means and means for maintaining a ow of supervisory current through said circuits insuicient to cause operation of said fault-indicating means, and interconnecting means for said circuits, to cause operation of either one of said indicating means in response to an interruption in the flow of supervisory current in the circuit of the other indicating means, and to additionally cause operation of one indicating means in response to the occurrence of a fault in the first-named circuit.

'6. In combination, an electrical circuit, independent normally closed electrical circuits each including fault-indicating means and separate sources of electrical energy for maintaining a flow of supervisory current through said first- Ynamed circuit as well as through said independent circuits insucient to cause operation of said fault-indicating means, and interconnecting means for said circuits to cause operation of either one of said indicating means in response to failure of the source supplying the supervisory circuit of the other indicating means, and to additionally cause operation of one indicating means in response to failure of the source supplying said rst-named circuit.

7. In combination, an electrical circuit, a rst fault-indicating signal, a second fault-indicating signal, means for maintaining a 110W of supervisory current through said circuit and both signals, with the value of said supervisory current insuilicient to cause operation of either signal, means responsive to interruption of supervisory current through the first signal to operate the second signal, and means responsive to interruption of supervisory current through said circuit or said second signal, to operate the first signal.

8. In combination, an electrical circuit, a first fault-indicating signal, a second fault-indicating signal, means for maintaining a flow of supervisory current through said circuit and both sig nals, with the value of said supervisory current insufficient to cause operation of either signal, and means including cross connections between said circuit and said signals whereby any interruption of supervisory current through the first signal serves to operate the second signal, and any interruption of supervisory current in said circuit, or through said second signal, serves to operate the first signal.

JOHN H. WHEELOCK. 

